The invention finds particular application where the signalling systems used by the telephone subset and the computer differ, as, for example, is the case where the telephone is a small business system (SBS) telephone. Such telephones are usually 4 wire telephones, having one pair for signalling and another pair for speech.
Many SBS systems use unique signalling methods between the subsets and the SBS switching equipment such as, for example, pulse string signalling, while a large number of personal computers use a standard signalling system.
It is desirable to incorporate telephone directory and call handling facilities into a personal computer so there will be no need for the telephone user to memorize various telephone numbers and call handling codes. These facilities can be displayed on the PC screen in the option menu format and selected as appropriate. For instance telephone directory information for internal and external calls can be stored in the computer and the computer can be programmed to emit dialling signals in the normal PC signalling code. Other features such as call forwarding, call back, hold etc. can also be included. However these signals will not be recognized by the SBS switching processor as it will only recognize signals in its own unique format.